This is a program project grant, centering around bone and bone mineral metabolism, calcium and phosphorus homeostasis, and their clinical applications. Laboratory studies and associated clinical studies have involved normal and abnormal collagen metabolism and turnover; calcium absorption and homeostasis; parathyroid hormone chemistry and assay, synthesis and action; vitamin D absorption and metabolism, and plasma transport; therapy of metabolic bone diseases, ectopic calcification syndromes, and renal calculi. In addition, the chemistry and synthesis of gonadotropins and prolactin, and the control of protein synthesis in liver have been investigated, and the support provided used for studies of mineralocorticoid homeostasis, androgen and estrogen metabolism, normal and abnormal pituitary release of TSH, ACTH, and growth hormone, autoantibody formation in irradiated patients, and studies of nodular goiter pathophysiology and vasopressin metabolism in man as well.